Recurrence quantification (RQA) for sway/trajectory analysis #357

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1. alexarje

   added a commit that references this issue on Aug 23, 2026

   Design: the road to 2.0, and what order the open issues get closed in

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2. alexarje commented on Aug 24, 2026

   

   alexarje

   on Aug 24, 2026

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   All three descriptors are in micromotion, and the last of them shipped today in 1.15.0. Markers are that package's domain under the four-toolbox rule and musicalgestures/_posture.py has been a re-export shim since 2026-07-29, so this closes with a pointer, as #356 and #358 did.

   Checked by running them, not by reading the API:

   this issue asked for	where it is	returns
   recurrence rate / determinism (RQA)	micromotion.dynamics.rqa	RR, DET, plus ENTR, Lmax, Lmean
   sway-axis rotation over a session	micromotion.sway_geometry + micromotion.circular.axial_dispersion	axis_deg per window; axial concentration across them
   heading persistence	micromotion.heading_persistence	persistence, straightness

   Two things worth knowing rather than discovering.

   rqa solves its threshold per plot for a fixed recurrence rate rather than using a fixed absolute one, so recordings of different amplitude are comparable — which the study script this came from did not do.

   Heading persistence reads backwards from the intuition. A sway that reverses along one line reads near +1, because it holds its heading through each excursion and turns only at the ends; standstill reads about 0.95. Reaching −1 takes a zigzag flipping at the sampling rate, which is a noise signature. Its docstring says so and a test pins it, because a reader who assumes "reversing means negative" would otherwise change the code to match. Two bugs in the first attempt were caught by those known-answer tests rather than by reading.

   It is also acutely sensitive to how a series was brought to its sampling rate: a bare polyphase resample read 0.15 for two 120 Hz editions against 0.95 for the rest. Use micromotion.to_rate.

   Import from micromotion directly. _posture re-exports only the functions that used to live in MGT, so these are not reachable through it — that is deliberate and its docstring says so.
3. alexarje

   closed this as completedon Aug 24, 2026